JPH01111908A - Construction of tiered form reventment - Google Patents

Abstract

PURPOSE:To construct simply a revetment by a method wherein the face of slope of the dyke is prepared in tiered form with a wave-breaking board partially equipped with a drainage being erected along the vertical plane of each tier, and concrete is placed on the horizontal plane of the tier to be integrated with the wave-breaking board and hardened together. CONSTITUTION:A back wall 1, a wave-breaking board 2 and a side wall 3 compose a molded form 4 having a drainage 5. To a revetment of which face of slope is prepared in tiered form, a plurality of molded forms 4 are arranged along the vertical plane of the tier with the wave-breaking board 2 protruding above the face of slope. Then, concrete is placed on the horizontal plane of the tier to harden the wave-breaking board 2 integrally. The device serves to construct easily a sea dyke capable of preventing scouring at the dyke body by storing temporarily the surged sea water in a storage 7 and controlling the flow of the reflected wave.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for constructing a stepped seawall in which a wave breaking plate extends from the upright surface of the stepped seawall, leaving drainage channels at regular intervals. According to the present invention, a permanent seawall can be obtained in which the reflected flow of seawater that has washed up on the seawall recedes is brought closer to a steady flow, thereby preventing the phenomenon of scouring and sucking out of the front surface of the seawall.

(Conventional technology) There have been many accidents in which seawalls, which have traditionally been installed on sandy beaches to prevent coastal erosion, are damaged.This is due to scouring in front of the foundation of the levee body due to strong reflected waves, and damage to the concrete of the levee body. It is known from experience that strong reflected waves flowing down the surface of the embankment are caused by the so-called suction phenomenon, which sucks out interstitial water in the embankment along with earth and sand from small gaps or cracks in the embankment body.

The present inventor believes that although all of these seawalls are made of strong concrete, they do not have strong walls to withstand the waves that hit the coast with a large amount of energy. Focusing on the fact that a seawall that weakens the energy and allows free flow of pore water on the back of the embankment body is stronger as a result, we developed Japanese Patent Publications No. 14125/1982, No. 14126/1983, and Publication No. 168805 of 1982 and Japanese Patent Application Laid-open No. 60-1983
In Japanese Patent Publication No. 168806, concrete blocks having a water storage section are placed in advance to temporarily pool seawater that washes up with waves and slowly release it until the next wave, and a large number of these concrete blocks are used to build an embankment body. We proposed a seawall that has a reflective flow control function by covering it.

[Technical problem to be solved by the invention]

The present invention provides a method for constructing a seawall having a reflected flow control function by directly placing concrete on the staircase surface without placing such concrete blocks in advance.

[Means of problem solving]

The structure of the present invention is that the slope is leveled in the shape of steps, and a molded body in which a sturdy wave-breaking plate is extended leaving a drainage channel on the rear wall at a height that covers the upright surface of the stairs is installed on the upright surface of the stairs. The method is characterized in that concrete is placed in close contact with the molded body and covered everywhere, and concrete is poured on the horizontal surface of the stairs and hardened integrally with the molded body.

In the present invention, the slope is leveled in advance into a staircase shape, and a molded body forming a rear wall is installed on the upright surface of the staircase prior to concrete pouring. This molded body has a sturdy wave-breaking plate extending from the upper end of the rear wall. The rear wall has a shape, preferably square, that can be joined laterally to completely cover the upright side of the staircase. In addition, a protrusion or a concave shape may be provided on the contact surface between the rear walls in order to make the joint more complete.

The wave-breaking plate does not extend from the entire upper end of the rear wall, but is provided at intervals of the drainage channel. The drainage channel should have a width that is not likely to become clogged due to the attachment of organisms such as shellfish and seaweeds, and a width of at least 70 mm, preferably 100 to 200 mm,
In some cases, more than this is required. Furthermore, since the wave-breaking plate is the part that receives the strongest wave energy, it is preferable that it has sufficient thickness and is tilted toward the land side. It may be provided at one end of the wave breaking plate, preferably at a portion of the wave breaking plate opposite to the drainage channel.

〔Example〕

FIG. 1 is a perspective view of a molded body that is placed on a staircase surface in advance when concrete is placed on a seawall. 4 is the rear wall 1,
It is a molded body consisting of a wave-breaking plate 2 and a side wall 3. The rear wall 1 has a height that matches the sum of the height of the stepped slope and the thickness of the concrete to be poured. The wave breaking plate 2 extends from the upper end of the rear wall leaving a drainage channel 5. It doesn't hurt to stand upright, but
Since it is a structure that protrudes from the seawall, if it is tilted slightly toward the land side as shown in the drawing, the impact from waves can be alleviated to some extent.

Figure 2 shows that the molded bodies shown in Figure 1 are arranged on the vertical surface of a stepped slope, the wave breaking plates 2 are made to protrude, and then concrete is poured on the horizontal surface of the stepped slope, and the molded bodies are integrated with the molded bodies. FIG. 3 is a cross-sectional view of the product after it has been cured. In this case, it is preferable that the side wall 3 contacts the horizontal surface of the stepped slope.

FIG. 3 is a plan view of FIG. 2. 6 is a concrete pouring surface, 7 is a water reservoir formed by the side wall 3 and the wave breaking plate 2, and 8 is a foot protection work. Waves crashing from the ocean are the second
As shown by the arrow in the figure, it crashed into the lowest wave breaking plate, and the wave breaking plate 2
a, fills the water storage part 7a, and then crosses the wave breaking plate 2b of the next stage to fill the water storage part 7b, colliding with the wave breaking plates one after another in this way, consuming energy, and filling the water storage part 7 with seawater. The amount of sea water will be reduced.

When the waves recede, if it is a normal seawall, the water will flow down rapidly, but in the seawall of the present invention, as shown by the arrow in FIG. Since the reflected flow passes through the channel 5 and flows down, it approximates a steady flow and can prevent scouring of the front surface of the embankment body.

According to the construction method of the present invention, all that is required is to level the slope in a step-like manner, arrange the structures 4 in close contact with the upright surfaces so as to completely cover the upright surfaces, and then pour concrete onto the horizontal surfaces 6. can be easily constructed.

FIG. 4 is a cross-sectional view of a seawall constructed using a structure without side walls. In the case of this embodiment, since the seawater stored in the water storage section 7 flows horizontally, it has the effect of offsetting the difference in seawater amount due to the local height of waves.

Furthermore, the seawater lateral flow phenomenon can prevent the accumulation of earth and sand on the seawall, making the construction easier.

In the above embodiment, the wave breaking plates were arranged in parallel and staggered so that the drainage channel was located between the drainage channels of the next stage, but it is not necessary to shift them in this way.
It may be a direct drainage channel.

〔effect〕

By placing concrete directly on the upright surface of a stepped slope, the present invention temporarily stores the energy of waves and seawater, adjusts the flow of reflected waves, avoids a projectile flow, and approximates a steady flow.
It is possible to prevent scouring of the embankment body foundation and construct a seawall that is stable over a long period of time using a simple method.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, in which FIG. 1 is a perspective view of a structure to be placed in advance, FIGS. 2 and 4 are cross-sectional views of a stepped slope, and FIG. 3 is a plan view of FIG. be. In the drawings, reference numeral 1 is a rear wall, 2 is a wave breaking plate, 3 is a side wall, 4 is a structure, 5 is a drainage channel, 6 is a horizontal surface, 7 is a water storage part, and 8 is a foot protection work. Patent Applicant Nippon Sohan Co., Ltd. Agent Patent Attorney Sadako Suzuki Figure 1

Claims (1)

[Claims] The slope is leveled into a stair-like shape, and a molded body with a sturdy wave-breaking plate extended from a drainage channel is left on the back wall at a height that covers the upright side of the stairs, and is closely attached to the upright side of the stairs. A method for constructing a stair-type seawall, which is characterized by covering the stairway and pouring concrete on the horizontal surface of the stairway and curing it together with the molded body.